What is a good prayer?

So I am sorta a Christian, I found God a few months ago, and I'm still trying to learn about him and be a woman of God, but between then and now there have been a lot of incidents that made me lose some faith in him. This past weekend I went to a church camp called Youth Haven Ranch, and they helped restore my faith in him, I haven't prayed since Sunday, and I know I should talk to God everyday. I really need help with what to pray about and how to do it. I start my prayers with Heavenly Father, .... Amen. I really need like a good starters prayer that has to do with him making me into the person he wants me to be, and asking for forgiveness for my sins, and for doubting him. I also want to add in to watch over my family, mostly my cousin who is in the hospital, and my friends. I know prayers should come from my heart, so I am not asking you to type me out one, I am just asking for like tips on a way to do it, how to put my words, and stuff like that?